This was a good piece. Normally I don't say that with anime styled Flash animations, but for the most part this actually worked very well. The lineart was smooth and the colours nice, the little bits of animation were nice little perks so kudos for that!
As for the sound, voices were for the most part very good. At the beginning with the little green haired girl though, the echo on her voice is very overpowering. You should tone it down if you are to ever use it in any future flash back scenes. The quality and volume of the red headed girls lines spiked a bit in some places, especially when she said 'yeah, pleaaase". But apart from that, voice acting and sound design fit very well.
Backgrounds and character designs were exceptional, and I love the colours you used for the backgrounds. I'd have liked to see a bit more shading on the characters in the cafe scene though, but since this is an anime style I'm not overly fussed about that. Lip sync was another thing that urked me a bit... but again, anime style. Lol. It would be good to see you try and sync the mouths to the voices properly in the future though.
Overall this has my interest and I know over time you'll only get better, so I've added you to my favourites so I can keep in touch with this. You have a great style here, just work on the small sound issues and I sense greatness for this.